Carbothermal reduction of silica in high temperature materials

摘要

The carbothermal reduction of SiO2 to silicon via a SiC intermediate. The SIO2/SiC interaction is described with the Si-C-O stability diagram and superimposed SiO(g) and CO(g) isobars. Si-saturated SiC and SiO2 generate much less total pressure of CO(g) and SiO(g) than C-saturated SiC and SiO2. In many situations, a finite amount of carbon is in contact with SiO2. If CO(g) is allowed to escape, the carbon activity will gradually decrease and the system will reach a point where P(CO) and P(SiO) are about equal. Experiments with C-saturated SiC and SiO2 powders and the reduction of oxide film on MoSi2 powders confirm these predictions.